This invention relates to front projection screens, and more particularly relates to such screens having a lenticular front surface.
The development of small display devices such as LCDs (liquid crystal displays) and DMDs (deformable mirror devices) suitable for reproducing video images, has given rise to the need for small aperture projection optics to project these images, and for front projection screens to display the projected images with adequate contrast over a wide viewing angle.
Various front projection screens are known which employ either a rear surface lenticular lens array or a linear fresnel lens array, together with light scattering particles to spread the image into the audience field. See, for example, U.S. Pat. Nos. 4,767,186; 4,964,695; and 4,911,529. These screens may also employ light-absorbing areas between the lens elements to absorb ambient light and thus improve image contrast.
One problem encountered with such small aperture systems is that light may pass through the screen without encountering any of the light scattering particles, giving rise to a phenomenon known as scintillation or speckle, which is the random occurrence of bright spots on the screen. Such scintillation or speckle is obviously undesirable in that it reduces definition, and is distracting to the viewer.